A kind of recycling method of waste lithium iron phosphate battery cathode material

Abstract

The invention provides a method for recycling a positive electrode material of a waste lithium iron phosphate battery, comprising the steps of: discharging the waste lithium ion battery, and separating the positive and negative electrode mixed powder, the battery shell, the copper foil, the aluminum foil and the diaphragm by a physical method; Add the separated positive and negative mixed powder into NaOH solution to dissolve, remove the residual Al element, and then put it in a certain concentration of organic acid solution to leach Li, Fe and PO. 4 3‑ , filter to remove insoluble graphite, separate the positive electrode material and negative electrode graphite material, and recycle the negative electrode material after purification; then add lithium source, iron source or phosphorus source according to the element ratio of the measured leachate to make Li:Fe:PO 4 3‑ The molar ratio is 1-1.05:1:1; then spray pyrolysis is carried out under a certain temperature condition and an inert gas atmosphere to obtain a carbon-coated lithium iron phosphate material. The invention simplifies the dismantling method, has high leaching efficiency, does not introduce impurity elements, and discharges waste gas mainly as CO 2 , which is conducive to industrialized large-scale production.

Description

technical field [0001] The invention belongs to the technical field of recycling waste lithium iron phosphate batteries, in particular to a method for recycling positive electrode materials of waste lithium iron phosphate batteries. Background technique [0002] With the advancement of new energy product technology, especially the demand for lithium-ion batteries in the electronic market and electric vehicle market is increasing year by year. As of the end of 2017, my country has promoted more than 1.8 million new energy vehicles and assembled about 86.9GWh of power batteries. Since 2018, lithium-ion batteries will gradually enter a large-scale decommissioning period, and there are a large number of lithium-ion battery disposal problems. However, waste lithium iron phosphate lithium-ion batteries contain reusable resources, such as lithium, aluminum, copper, iron and other valuable metals and graphite and other materials. If these batteries are not handled properly, it will ...

AI Technical Summary

Problems solved by technology

One is to use manual disassembly to separate the positive and negative pole pieces, scrape off the powder, and then recover the lithium compound and iron phosphate respectively through acid leaching and pH adjustment. CN108470952A, CN108461857A, etc., in these disclosed treatment methods, the lithium iron phosphate material is not regenerated in situ, but the lithium element and the iron element are recovered separately, the consumption of acid and alkali is large, the recovery cost is high, and the treatment of the three wastes is difficult

Another method is to directly add lithium source, iron source or phosphorus source to prepare lithium iron phosphate material after calcining, such as the documents CN108550940A, CN108172922A, CN107634222A, CN107275705A, CN106976852A, etc. disclosed by the Chinese Patent Office. High requirements (requires relatively pure positive electrode powder), the uniformity of the newly prepared material particles is difficult to ensure and is prone to impurity, and the electrochemical performance of the positive electrode material cannot be guaranteed

Another method is the document CN106276842A disclosed by the Chinese Patent Office, which is an in-situ synthesis of lithium iron phosphate precursor after leaching with an organic mixed acid, but it needs to be prepared by vacuum distillation and organic solvent precipitation, and the process is complicated, energy consumption is high, and recovery costs High, difficult to achieve industrial production

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